Methodological evaluation of ELISA and RPR for the detection of antibodies against treponema pallidum

Objective To investigate the value of enzyme-linked immunosorben assay(ELISA)and rapid plasma reagin test(RPR)in the diagnosis of syphilis.Methods Each of three serological tests including RPR,ELISA and treponema pallidum particle assay(TPPA)was employed to detect the serum antibodies against treponema pallidum in 400 patients with syphilis respectively.And the diagnostic value was compared between RPR and ELISA with TPPA as a gold standard.Results There was a significant difference in the detection result between RPR and TPPA method(P0.001,χ2=17.361),while no marked difference was noted between ELISA and TPPA method(P=0.065,χ2=0.250).The sensitivity,specificity,positive and negative predictive values and Kappa coefficient were 65.1%,98.4%,92.1%,90.8% and 0.71 respectively for RPR,and 98.9%,99.0%,96.7%,99.7% and 0.97 for ELISA.Conclusion ELISA for the detection of antibodies against treponema pallidum possesses higher sensitivity,specificity and accuracy,and can be applied to preliminary screening in batches in the clinical settings and the final diagnosis of treponema pallidum infection.